A conventional refrigerator is disclosed in Japanese Patent Application Laid-Open No. H8-145545. According to this publication, inside a refrigerator is provided an ion generating device having an opposed electrode that attracts electric charge, and a negative direct-current high voltage is applied to the opposed electrode to produce negative ions. The negative ions are discharged into a storage compartment so as to restrain the proliferation of bacteria floating inside the storage compartment and thereby keep the food stored therein fresh.
In this conventional refrigerator, the ion generating device has an opposed electrode arranged so as to be opposed to a needle-like electrode. The ions discharged from the needle-like electrode into the narrow space between the needle-like and opposed electrodes are attracted by the opposed electrode. Thus, to discharge the desired number of ions required to kill bacteria into the storage compartment, it is necessary to use a large-size blower that has a high blowing ability. That is, one problem with this conventional structure is that the provision of the opposed electrode and the large-size blower tends to make the ion generating device complicated and large.
Moreover, when the needle-like electrode is charged with a negative voltage to selectively generate a large number of negative ions, the electric circuit is charged with positive electric charge. This causes failure of the electric circuit resulting from its being charged, and lowering of the number of generated negative ions under the influence of the positive electric charge. To avoid this, it is necessary to let the positive charge escape by securing direct grounding to the earth. Thus, another problem with the conventional structure is, in refrigerators for home use, it is difficult to secure direct grounding to the earth in all households because of restraints associated with the design, location, and the like of their homes.